物种灭绝对不同时间尺度人类活动的响应机制研究

通过修改Tilman的多物种共存的经典模式中栖息地毁坏率（D），使D随时间的推移呈线性增长情况下，本文模拟了百万年、万年和百年尺度人类活动对栖息地的破坏下，物种灭绝对栖息地毁坏的响应特征。结果表明，大时间尺度人类活动对栖息地毁坏导致物种的强弱关系发生变化，并且强物种先灭绝，而小时间尺度人类活动对栖息地破坏是弱物种先灭绝；在百万年和万年尺度上，物种对栖息地毁坏的响应是减幅振荡衰退直至灭绝，并且最强物种对栖息地的占有率（q）越大，振幅越大，而在百年尺度上，物种的演化几乎是直线衰退；在大时间尺度的栖息地毁坏情况下，q越大，则物种灭绝起始时间和所有物种灭绝的时间越长；而在较小的时间尺度的栖息地毁坏情况下，q越大，灭绝起始时间和所有物种最终灭绝的时间则越短。

Responsive mechanism of species extinction to the habitat destruction at different time scales

The greatest threat to the survival of species worldwide is the loss of suitable habitat.By the modified Tilman's analytical model of competitive coexistence in multispecies community,we simulated the species responses to the habitat destruction at million-year,ten-thousand-year and hundred-year time scales.The results showed that habitat destruction at million-year and ten-thousand-year time scales would be led to the competitive abilities changed,and the stronger species would be extinct earlier than the poorer species.While at hundred-year time scale species would be driven to extinction in the order from the originally poorest to the originally strongest.At million-year time scale and ten thousand-year time scale,species would oscillate quasi-periodically and decline to extinction with time,and the amplitudes along with quasi-periods of species evolution would polarize more obviously increased with q(the proportion of occupied habitat of the best species).At hundred-year time scale,the species evolutionary curves would not oscillate.At larger scale,the extinction time would increase with q,while the extinction time of species would become much shorter with q increased in the case of a smaller scale.